Rotary die and cutting rule

ABSTRACT

An improved rotary die and steel cutting rule are provided. The die includes a die plate of precise, uniform thickness throughout its length and width, with the thickness of all die plates being consistent. The steel cutting rule for the die plate includes a metal strip having an upper cutting edge and a structurallyintegral flange formed at substantially right angles to the cutting strip with the juncture of the flange and the strip being parallel to the upper cutting edge. The flange of the cutting rule is provided with suitable openings to receive fasteners by means of which the flange is fastened to the upper surface of the die plate. The cutting rule can be provided with a projection or projections on or adjacent the flange to penetrate the upper surface of the die plate to aid in holding the cutting rule in a predetermined position on the die plate.

United States Patent [191 Saunders [45] Feb. 19,1974

[ ROTARY DIE AND CUTTING RULE [75] Inventor: Philip G. Saunders, Toledo,Ohio [73] Assignee: Container Graphics Corporation,

Toledo, Ohio [22] Filed: June 7, 1972 [21] Appl. No.: 260,482

[52] U.S. Cl 83/673, 83/55, 83/346 [51] Int. Cl B26d 1/12, B23d 35/00[58] Field of Search 83/55, 331, 343, 344, 346,

l/l942 l/197l Parks, Jr.... 83/677 Boyd 83/347 X Primary Examiner-WillieG. Abercrombie Attorney, Agent, or Firm-Allen D. Gutchess, Jr.

[5 7] 7 ABSTRACT An improved rotary die and steel cutting rule areprovided. The die includes a die plate of precise, uniform thicknessthroughout its length and width, with the thickness of all die platesbeing consistent. The steel cutting rule for the die plate includes ametal strip having an upper cutting edge and a structurallyintegralflange formed at substantially right angles to the cutting strip withthe juncture of the flange and the strip being parallel to the uppercutting edge. The flange of the cutting rule is provided with suitableopenings to receive fasteners by means of which the flange is fastenedto the upper surface of the die plate. The cutting rule can be providedwith a projection or projections on or adjacent the flange to penetratethe upper surface of the die plate to aid in holding the cutting rule ina predetermined position on the die plate.

7 Claims, 6 Drawing Figures ROTARY DIE AND CUTTING RULE This inventionrelates to a cutting die and particularly to rotary dies having cuttingrules affixed to the surface thereof.

Dies of the type under consideration are employed to shape and cut sheetmaterial, commonly corrugated board, into preformed blanks from whichvarious types of containers, packages, etc., are subsequently made.Rotary dies are now being increasingly used over flat ones particularlybecause of the higher production rates achieved with the rotary dies. Inthe rotary die machine, a pair of cylinders are mounted in a support ingframe with a predetermined space therebetween. One of the cylinderscarries a die plate having the desired cutting rules, perforating rules,and creasing rules mounted therein, in predetermined positions. Theother cylinder has a yieldable pad or layer of plastic thereon whichsupports the corrugated board as it is fed between the cylinders duringrotation of them.

To produce a blank of a predetermined shape for a particularapplication, the rotary die must be carefully fabricated with thevarious cutting, creasing, and perforating rules accurately positionedin the die plate. To achieve this, an arcuate die plate is firstprovided on which is laid out the appropriate shape of the desiredblank, including lines for cuts, perforations, and folds. The layout forthe die plate is accomplished with the aid of a special layout machinewhich compensates for the arcuate shape of the die plate to provideproper spacing between the cutting and other rules in spite of thearcuate configuration of the plate. Heretofore, saw cuts were made inthe die plate along the particular layout lines to provide slots in theproper locations for receiving the cutting rules, perforating rules, andcreasing rules. These slots had to be discontinuous in order to formbridges at intermediate portions of the slots which provided structuralcontinuity between the various por tions of the die plate. The rulesthen had to be notched at the appropriate locations to fit over thesebridges and into the slots, with the lower edges of the rules seatedagainst the die cylinder on which the die plate was mounted. Thisenabled the upper edges of the rules to always be at a fixed distancefrom the die cylinder even if the die plate itself varied in thickness,either from plate to plate or over the length or width of one plate.

Fabrication of dies in this manner was time consuming, particularly inproducing the slots in the plate which not only had to be accurate butcarefully made to provide the proper bridges. Further, any error in thepositioning of the saw slots often meant that the die plate had to bescrapped. The proper positioning of the notches in the rules to matchthe die plate bridges also was time consuming. Additionally, the bridgesin the die plate would sometimes break, due to being weakened when thecutting rules were forced into the slots or because the rules would biteinto and weaken the bridges during operation. The breaking of thebridges would cause the rules to fly out of the cutting die, presentinga hazard. In some instances even the steel rule itself would break atthe bridge and cause an overlap or other mis-matching of the rule atthis location. In addition to this problem of the broken bridge or rule,at times when the rule was forced down against the metal cylinder onwhich the die plate was mounted, the effective length of the rule wouldchange and result in a shaped or cut blank of incorrect dimensions.

In accordance with the invention, a rotary die is provided constitutinga die plate of a uniform, predetermined thickness with cutting rulesaffixed to the surface thereof rather than being mounted in slots. Withthe cutting rules mounted on the surface, the saw cuts heretoforenecessary are eliminated entirely, resulting in substantial savings intime and labor and reduced waste and improperly cut die plates. Theproblems of broken bridges and cutting rules broken at the bridges arealso eliminated. Further there is no possibility that the effectivelength of the rules will be changed when mounted on the die plate slots.

The new cutting rule is preferably made from a single, elongate metalbody having a metal strip with an upper cutting edge and astructurally-integral flange formed at the bottom of the cutting stripat substantially right angles thereto with the juncture of the flangeand the strip being parallel to the upper cutting edge. The flange inone embodiment can be part of the metal strip bent out of the planethereof to the right angle position with the strip then formed to thedesired arcuate shape. Alternatively, the strip and flange can beextended in a generally right angular, cross-sectional shape. In eithercase the flange is at right angles to the cutting strip portion of thecutting rule and has suitable openings formed therein to receivefasteners for affixing the flange to the surface of the die plate.Further, if desired, the flange or portions of the cutting rule near theflange can be provided with downwardly-extending projections whichpenetrate or bite into the surface of the die plate to aid in holdingthe cutting rule in position thereon during operating.

It is, therefore, a principal object of the invention to provide animproved cutting die which can be made with less time and labor.

Another object of the invention. is to provide a cutting die which canbe made less expensively and with less waste.

Yet another object of the invention is to provide a cutting rule for acutting die having a flange by means of which the cutting rule can beaffixed to the surface of the die plate of the die.

A further object of the inventin is to provide an improved cutting rulehaving a cutting strip with an upper cutting edge and a flange extendingat right angles to the cutting strip, which flange has means foraffixing the cutting die to the upper surface of a die plate.

Yet a further object of the invention is to provide a cutting die inwhich the cutting rules are fastened to the die plate in a manner toreduce possible breakage of the rule or the die plate.

Many other objects and advantages of the invention will be apparent fromthe following detailed description of preferred embodiments thereof,reference being made to the accompanying drawings, in which:

FIG. 1 is a schematic view in perspective of a rotary die machineembodying the invention;

FIG. 2 is a somewhat enlarged view in perspective of a rotary steel rulecutting die shown in FIG. 1;

FIG. 3 is an enlarged view in perspective of a modified rotary cuttingrule and a fastener for fastening the rule to a die plate in accordancewith the invention;

FIG. 4 is an enlarged view of a further modified steel cutting rule andfastener embodying the invention; and

FIGS. 5 and 6 are enlarged views in perspective of further modifiedcutting rules embodying the invention.

Referring particularly to FIG. 1, a rotary die machine is indicated at10 and includes an upper die cylinder 12 and a lower, back-up cylinder14. A resilient plastic layer 16 is mounted on the back-up cylinder 14and the cylinders are rotatably mounted on a frame or stand 18 and canbe adjusted by means (not shown) so that the space between them can bevaried. In operation, the cylinders are rotated in the directions of thearrows by suitable drive means (not shown). Corrugated board or othersuitable sheet material is fed between the cylinders 12 and 14 where itis engaged by a rotary cutting die 20 and shaped and formed into a blankfrom which containers or other products can be formed or fabricated.

A rotary cutting die 20 (FIG. 2) basically includes a die plate or board22 from which steel cutting rules 24 project. Other types of rules suchas creasing rules and perforating rules are not shown in this instance.The die plate 22 is of a predetermined thickness with that thicknessbeing constant throughout its length and width. When the die plate ismade of high quality plywood, and formed to the arcuate shape as shown,the actual thickness may vary slightly from board to board and also overthe area of an individual board. The board can be made of apredetermined and uniform thickness, however, by suitably finishing thesurface such as by mounting the board on a cylinder on a lathe, andmachining and sanding the surface to achieve the proper thickness. Ifthe board is made of plastic material, such as shown in a copendingapplication of J. R. Simpson, Ser. No. 213,016, the desired dimensionsusually can be achieved when the board is made without further machiningor other steps being necessary.

With the die plate having a predetermined, uniform thickness, it ispossible to lay out directly on the surface thereof the lines by meansof which the cutting rule are to be positioned. The layout can bedirectly on the die plate surface since the dimensional changes requiredto compensate for the radius of curvature of the die plate can bereadily determined and a scale set accordingly. Consequently, noexpensive layout machine is needed, as required with the usual dieplates varying in thickness. With the layout lines on the surface, thecutting rule 24 according to the invention can be positioned thereon andaffixed to the die plate 22 without saw cuts being required at all. Thesaw cuts, bridges, and special notches in the steel cutting rules neededto fit over the bridges are thereby eliminated, along with the time andlabor required for same.

Since the saw cuts are eliminated, there is also greater freedom in theplacement of the cutting rules 24. For example, as shown, the cuttingrules can be placed closer to the edges of the die plate 22. Thisreduces the size requirements for the die plates in some instances andresults in further saving in material.

Each of the cutting rules 24, as shown in FIG. 2, comprises an elogatesteel cutting strip or portion 26 having a serrated cutting edge 28formed at the upper edge thereof. A flange or transversely extendingportion 30 is structurally integral with the strip 26 and formed atsubstantially right angles thereto. The juncture of the flange 30 andthe strip 26, indicated at 32, is parallel to the cutting edge 28. Inthis instance, the flange 30 has notches 34 forming tabs 36 with certainones of the tabs 36 having openings (not shown) to receive fasteners 38.For the cutting rules extending circumferentially or having acircumferential component of direction, the arcuate shape thereof can beformed by passing the cutting rule through a three-roll bender toestablish the desired arcuate shape, as is generally known in the art.The cutting rules 24 can be made in three shapes: straight, with a fullarc when extending circumferentially, or with a shallower are whenextending at a 45 angle relative to the axis of the die cylinders.

When the cutting rule is to be used to form a slot or elongate notch inthe corrugated board blank, a cutting rule indicated at 40 can beemployed. This cutting rule is similar to the other rules 24 but thestrip portion 26 is bent back on itself at 42 to provide the desired U-shaped configuration. The notch 34 at the bend 42 can be cut slightlydeeper, extending to the juncture 32, to provide the proper bend for thestrip 26. At the corners, the flange 30 can be notched on a diagonal,generally as indicated at 44 to provide the properjunction.

Referring to FIG. 3, a slightly modified cutting rule is indicated at46. This cutting rule again has a cutting portion or strip 48 with anupper cutting edge 50 and a flange or transversely extending portion 52extending outwardly at right angles from a juncture 54, the flange 52 inthis instance being solid. Suitable openings 56 are punched or otherwiseformed in the flange 52 to receive serrated fasteners 58, by way ofexample.

A modified cutting rule 60 in FIG. 4 is similar to the cutting rule 24except that it has openings or holes 62 formed at the ends of thenotches 34. In this instance, staples 64 are designed to fit into pairsof the openings 62 to affix the cutting rule 60, to the die platesurface. These are sized to extend through the holes 62 in a manner toprevent any lateral movement of the cutting rule 60.

A modified cutting rule 66 is shown in FIG. 5, the rule 66 beingextruded, in this instance. The rule 66 includes a cutting portion orstrip 68 having a cutting edge 70 and a transversely extending portionor flange 72 extending at right angles thereto, with openings 74 forreceiving fasteners. The cutting rule 66 has a projecting ridge 76 atthe juncture 78 of the flange and cutting strip. This projection isdesigned to bite into the surface of the cutting die plate and to aid inholding the cutting rule in position.

Referring to FIG. 6, a further modified cutting rule 80 is shown, beingmade of steel. This rule 80 includes a cutting strip or portion 82having an upper cutting edge 84. Flanges or transversely extendingportions 86 are bent outwardly in both directions substantially at rightangles to the strip 82 with elongate openings 88 therein to receivefasteners, such as the fasteners 58 of FIG. 3. The flanges 86 in thisinstance include outer portions 90 which are in direct contact with thedie plate surface, these portions lying in a common plane, and innerportions 92 which extend upwardly from the die plate at slight anglesthereto. This configuration of the flanges 86 provides a somewhatyieldable mounting to enable the cutting strip 82 to give somewhat tomake up for wear and slight variations in the distance from the cuttingedge 84 to the surface of the die plate 22. With the holes 88 beingelongate, the outer flange portions 90 can move slightly with respect tothe fasteners to enable the yieldability to occur.

Various modifications of the above-described embodiments of theinvention will be apparent to those skilled in the art and it is to beunderstood that such modifications can be made without departing fromthe scope of the invention, if they are within the spirit and the tenorof the accompanying claims.

I claim:

1. A die assembly comprising a die plate having a predetermined, uniformthickness, a cutting rule comprising a metal cutting portion having anupper cutting edge and a structurally-integral, transversely-extendingportion extending substantially outwardly therefrom, said cutting rulehaving a downwardly-extending projection which penetrates the surface ofsaid die plate when said cutting rule is affixed thereto, saidtransverse portion having fastener openers therein, and fastenersextending through said openings and affixing said cutting rule to thesurface of said die plate.

2. An arcuate cutting rule comprising an elongate, formed metal bodycomprising an arcuate metal strip having an upper arcuate cutting edgeand a structurally-integral flange at substantially right angles to saidstrip, the juncture of said flange and said strip being parallel to theupper cutting edge, said cutting rule having means for affixing saidrule to a die plate, and said cutting rule having a projection extendingdownwardly perpendicularly generally away from said flange and adaptedto penetrate the surface of the die plate to which the cutting rule isto be affixed.

3. A cutting rule according to claim 2 characterized by said affixingmeans comprising openings in said structurally integral flange.

4. An arcuate cutting rule according to claim 2 characterized by saidstrip and said flange being of extruded metal.

5. A die assembly comprising a die plate having a predetermined, uniformthickness, a cutting rule comprising a metal cutting portion having anupper cutting edge and a structurally-integral, transversely extendingportion extending substantially outwardly therefrom, said transverseportion having a plurality of spaced, generally V-shaped notches formedtherein, fastener openings formed at the ends of said notches, andfasteners extending through said openings and affixing said cuttingrules to the surface of said die plate.

6. An arcuate cutting rule comprising an elongate, formed metal bodycomprising an arcuate metal strip having an arcuate cutting edge and astructurally integral flange extending at substantially right angles tosaid strip, the juncture of said flange and said strip being parallel tothe upper cutting edge, said flange having portions extending inopposite directions from the plane of the metal strip, said flangehaving outer portions and inner portions, the latter extending upwardlyat slight angles to the outer portions, said outer portions havingfastener openings therein.

7. An arcuate cutting rule according to claim 6 characterized by saidfastener openings being elongate in said outer portions with theirlongitudinal extent being substantially perpendicular to the plane ofsaid metal strip.

1. A die assembly comprising a die plate having a predetermined, uniformthickness, a cutting rule comprising a metal cutting portion having anupper cutting edge and a structurally-integral, transversely-extendingportion extending substantially outwardly therefrom, said cutting rulehaving a downwardly-extending projection which Penetrates the surface ofsaid die plate when said cutting rule is affixed thereto, saidtransverse portion having fastener openers therein, and fastenersextending through said openings and affixing said cutting rule to thesurface of said die plate.
 2. An arcuate cutting rule comprising anelongate, formed metal body comprising an arcuate metal strip having anupper arcuate cutting edge and a structurally-integral flange atsubstantially right angles to said strip, the juncture of said flangeand said strip being parallel to the upper cutting edge, said cuttingrule having means for affixing said rule to a die plate, and saidcutting rule having a projection extending downwardly perpendicularlygenerally away from said flange and adapted to penetrate the surface ofthe die plate to which the cutting rule is to be affixed.
 3. A cuttingrule according to claim 2 characterized by said affixing meanscomprising openings in said structurally integral flange.
 4. An arcuatecutting rule according to claim 2 characterized by said strip and saidflange being of extruded metal.
 5. A die assembly comprising a die platehaving a predetermined, uniform thickness, a cutting rule comprising ametal cutting portion having an upper cutting edge and astructurally-integral, transversely extending portion extendingsubstantially outwardly therefrom, said transverse portion having aplurality of spaced, generally V-shaped notches formed therein, fasteneropenings formed at the ends of said notches, and fasteners extendingthrough said openings and affixing said cutting rules to the surface ofsaid die plate.
 6. An arcuate cutting rule comprising an elongate,formed metal body comprising an arcuate metal strip having an arcuatecutting edge and a structurally integral flange extending atsubstantially right angles to said strip, the juncture of said flangeand said strip being parallel to the upper cutting edge, said flangehaving portions extending in opposite directions from the plane of themetal strip, said flange having outer portions and inner portions, thelatter extending upwardly at slight angles to the outer portions, saidouter portions having fastener openings therein.
 7. An arcuate cuttingrule according to claim 6 characterized by said fastener openings beingelongate in said outer portions with their longitudinal extent beingsubstantially perpendicular to the plane of said metal strip.